docs: fill all missing documentation

[Copilot]

Overview

This PR addresses issue #[issue_number] by filling in all missing documentation that was previously marked with "TODO add documentation" comments throughout the codebase.

Changes Made

Added comprehensive KDoc documentation for the following components:

Entry Points

• JVM Main.kt: Documented the main() function as the entry point for the JVM platform, explaining it starts 3 devices with IDs from 0 using the IO dispatcher for MQTT communication
• JavaScript Main.kt: Documented the main() function as the entry point for the JS/Node.js platform, explaining it starts 2 devices with IDs from 2 using the Default dispatcher

Core Logic (CommonEntrypoint.kt)

• aggregateProgram(): Documented the function that defines the aggregate program logic, which collects neighbor IDs discovered through MQTT network communication
• mainEntrypoint(): Added detailed documentation for the main execution logic that creates and manages a distributed network of devices, including comprehensive parameter descriptions for:
  • roundTime: Duration between computation rounds
  • executeFor: Total system runtime before shutdown
  • startDeviceId: Starting device ID for sequential assignment
  • deviceCount: Total number of devices in the network
  • asyncNetwork: Whether to run computations asynchronously or at fixed intervals
  • dispatcher: Coroutine dispatcher for execution

Network Components

• AbstractSerializableMailbox: Documented the abstract base class that provides common implementation for network-based mailboxes, handling message serialization/deserialization, neighbor management, and message retention
• MqttMailbox: Added comprehensive documentation explaining:
  • The MQTT-based mailbox implementation for distributed device communication
  • Management of neighbor discovery through MQTT topic subscription
  • Message publishing and receiving via MQTT
  • Connection lifecycle to the MQTT broker
  • Companion object factory methods and the invoke() operator for creating initialized instances

Verification

All changes have been verified to:

• ✅ Pass all linters (detektAll, ktlintCheck)
• ✅ Build successfully on all platforms (JVM, JS)
• ✅ Follow KDoc conventions and Kotlin coding standards
• ✅ Provide clear, comprehensive explanations of purpose, parameters, and return values

No "TODO add documentation" comments remain in the codebase.

Original prompt

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This section details on the original issue you should resolve

<issue_title>docs: fill all missing documentation</issue_title>
<issue_description>In several places, there are comments like TODO: write doc.
Write all the required documentation instead.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #138

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